Field of the Invention
The invention relates to a configuration for determining the dimensions of printed media, especially of letters or envelopes, in a letter or envelope separating apparatus. In that case, the letters or envelopes can have different thicknesses and permissible formats in an irregular sequence. The processing of letters or envelopes occurring in that way is referred to as mixed mail operation.
Mail processing systems normally include:
a letter or envelope separating apparatus, in which the letters or envelopes are placed successively in stacks, separated and closed as required,
a franking and/or addressing machine with an optional integrated or preceding balance or scale, and
a depositing apparatus.
Reference is made in that regard to German Design Application DE-M 96 09 167.3 in the Registered Design Bulletin of the German Patent Office, dated May 24, 1997, Part Ia, Goods Class 18/02.
In order to determine the necessary postage, various postal carriers need information relating to the dimensions of the letter or envelope, in addition to the destination, the class of mail and the weight.
An apparatus for measuring the thickness of an item of mail is known from European Patent EP 0 376 496 B1. During operation, that apparatus is coupled to a separating apparatus. The separating apparatus essentially includes a stationary circulating transport belt and a movable retaining belt running in the opposite direction, which is deflected in accordance with the thickness of the item of mail. The thickness measuring apparatus has a part which produces a connection with the separating apparatus, in particular with the retaining belt, and can be moved with the latter, as well as a stationary part. The measured thickness is related to the extent of the relative movement between the movable and the stationary parts. The movable part has a magnet and the stationary part has a magnetic field detector.
In addition, an apparatus is known from European Patent EP 0 548 874 B1, for measuring the thickness of a letter sheet moving in a folding and inserting machine for documents before franking. That apparatus operates with a sensing device which supplies electrical signals. The sensing device includes a pair of rollers through which the letter sheet passes. One of the rollers is pivotably mounted on a sensing lever, which is permanently connected to a flag. The flag interacts with a light source and a light detector which responds to the light beams. The flag includes a sector with numerous slits and is disposed in such a way that, through the use of nontransparent areas between the slits, it covers light beams which are directed toward the detector. The detector is an optical encoder, which delivers pulses each time a slit in the flag passes in front of the encoder. The optical encoder is an incremental encoder having two output channels, which are located in phase quadrature and give a signal transition when the thickness varies by a few hundredths of a millimeter. However, only one dimension of the letter is determined with both of the above-described apparatus.
On the other hand, an apparatus for measuring the length, the width and the height of box-like conveyed products is known from German Published, Non-Prosecuted Patent Application DE 196 10 631 A1, in which, for that purpose, sensors are provided that have a transmitting and receiving part and a direction of measurement which is oriented perpendicularly to side surfaces of the conveyed product, which rests in a predetermined attitude on a holding element. The sensors being used are three distance sensors, having directions of measurement that are in each case perpendicular to one another. The holding element essentially includes a baseplate and stop elements for orienting the conveyed product on the baseplate. The distance between the directions of measurement of the sensors and the associated stop elements in each case is about 1 to 50 mm. The distance sensors are constructed as ultrasonic sensors and have circuits working on the echo-sounding principle. In that case, the distance between the direction of measurement and the stop element is preferably 20 mm.
Another variant provides for optical distance sensors. That apparatus can be used only for static and not for continuous operation, in accordance with the feeding conditions for the conveyed products. Furthermore, because of the minimum distance of the directions of measurement from the stop elements, that apparatus is suitable only for packages and not for thin letters or envelopes. Added to that is the fact that a different finish of the material for the envelopes can result in different ultrasonic reflection properties and, consequently, erroneous measurement results can occur.
Furthermore, a franking machine is known from German Utility Model DE 297 16 523 U1, which has a digital printing device, a guide plate and a transport apparatus with a transport belt for printed media, as well as a control device. The control device is used to generate printing signals for a printing head in order to print the surface of the printed medium with an appropriate printed image while the printed medium is transported past the printing head. A pressure sensor in the guide plate is disposed in front of a recess for the printing head. In addition, a preparation sensor is disposed upstream in the guide plate, at a specific distance in front of the pressure sensor. The preparation sensor is constructed as a reflected light barrier, and the pressure sensor is constructed as a transmitted light barrier.
The control device includes a microprocessor, to which an encoder for determining the travel of the transport belt and a number of sensors are connected, with the latter being located at intervals from one another upstream of the printing head. The microprocessor is programmed to determine a valid letter format or a fault on the basis of interrogating the preparation sensor and the pressure sensor and determining the travel of the belt. The microprocessor determines the length of a letter or envelope from the difference between the value for the leading edge of the letter and the value for the trailing edge of the letter. A fault message is output if the length of the letter is greater than the predetermined travel of the belt, or if the length of the letter is less than the predetermined imprint length. Since the length of the letter has to be taken into account in calculating the postage and, consequently, in creating the imprint, an appropriate expenditure on the microprocessor is necessary if the letter transport speed is not to be restricted significantly. With that configuration, likewise only one dimension of the letter is determined.
Furthermore, a configuration for pre-separating printed media is known from German Published, Non-Prosecuted Patent Application DE 196 05 017 A1, in which the letters or envelopes, standing on one edge, are deposited one after another as a letter stack, and the letters are fed laterally away from the letter stack to a separating apparatus. In that case, the letters or envelopes are disposed between a spring-mounted pressure clip and at least one drive roll and a guide plate which is inclined slightly rearward. The standing surface for the letters and the guide plate are orthogonal to each other.
Finally, a further apparatus for separating printed media, especially letters or envelopes, has been found, corresponding to German Published, Non-Prosecuted Patent Application DE 198 36 235 A1, corresponding to U.S. application Ser. No. 09/368,645, filed Aug. 5, 1999. That apparatus will be explained in more detail below with regard to FIG. 1.
The purpose of the invention is to improve the function and to widen the field of use.
It is accordingly an object of the invention to provide a configuration for determining the dimensions of printed media, which overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices of this general type, in which elements of a separating apparatus can largely be utilized at the same time and in which the technical outlay and space requirement is as low as possible.
With the foregoing and other objects in view there is provided, in accordance with the invention, in a separating apparatus for printed media, especially letters or envelopes, including a guide plate on which the printed media rest in stacked form and along which the printed media are transported laterally, and a following device downstream of the guide plate, a configuration for determining dimensions of the printed media, comprising a device for scanning the printed media and determining dimensions of the printed media; and an ejector for transferring the printed media from the guide plate to the following device, the ejector included in the scanning of at least one dimension of the printed medium.
In accordance with another feature of the invention, the ejector is a pair of ejection rolls including a stationary driven ejection roll and a spring-adjustable indirectly driven ejection roll; at least one first optical sensor for determining height of the printed media is disposed in the guide plate, upstream of the pair of ejection rolls, at a distance smaller than a shortest printed medium length to be expected; an encoder sensor is connected synchronously to the indirectly driven ejection roll and has a number of revolutions per printed medium used for printed-medium length measurement; a second optical sensor is connected to the indirectly driven ejection roll for using a deflection of the ejection roll by the printed medium guided between the pair of ejection rolls for printed-medium thickness measurement; a third optical sensor is disposed directly in the vicinity of the pair of ejection rolls, is used to detect a start and an end of a printed medium in the ejection area and is linked electrically to the first optical, second optical and encoder sensors for activating the first optical, second optical and encoder sensors at the start of the printed medium and deactivating the first optical, second optical and encoder sensors at the end of the printed medium, to detect the dimensions of the printed medium; and an evaluation circuit is disposed in the separating apparatus, is electrically connected to the first optical, second optical, third optical and encoder sensors for transmitting measurement results and is electrically connected to the following device, such as a scale or a franking machine.
In accordance with a further feature of the invention, the at least one first optical sensor is many sensors disposed in a chain one above another, corresponding to usual formats, for determining the height of the printed media.
In accordance with an added feature of the invention, the at least one first optical sensor is a reflection sensor.
In accordance with an additional feature of the invention, there is provided a rotatable shaft and a carrying lever for the indirectly driven ejection roll; the encoder sensor for printed-medium length measurement having an encoder disk and an evaluation unit with a photocell; the encoder disk and the indirectly driven ejection roll jointly fixed on the rotatable shaft; and the evaluation unit fixed underneath the encoder disk on the carrying lever.
In accordance with yet another feature of the invention, there is provided a carrying lever having a shaft, the second optical sensor for printed-medium thickness measurement having an analog reflection sensor and a reflection marker fixed to the carrying lever opposite the stationary reflection sensor, in the vicinity of the shaft of the carrying lever.
In accordance with yet a further feature of the invention, there is provided a carrying lever having a shaft, the second optical sensor for printed-medium thickness measurement having a digital transmitted-light sensor and a flexible, graduated, transparent rule guided in the second optical sensor and fixed to the carrying lever in the vicinity of the shaft.
In accordance with a concomitant feature of the invention, the ejection rolls define a line of contact therebetween, and the third optical sensor for detecting printed media is disposed immediately upstream or downstream of the line of contact.
For the first time, during the transport of the letter or envelope in a separating apparatus, before weighing and at a sufficiently long time before the franking, all of the dimensions of the letter or envelope are determined, so that there is sufficient time to accommodate the postage value in the franking imprint without having to place particularly high requirements on the computing technology needed therefor. Through multifunctional use of the indirectly driven ejection roll, including its accessories, a measurement of thickness and length is achieved without demanding any additional space and with a low outlay. At the same time, astonishingly accurate results are achieved.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a configuration for determining the dimensions of printed media, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.